#include <string>
using namespace std;
struct Tuble
{
	int t1;
	int t2;
};
int abs(int n);
Tuble func(int init_val);
size_t count_calls();
void swap(int *p1,int *p2);
void reset(int &p);
void has_upper(const string &s);
void to_lower(string &s);
void print(int (&arr)[10]);
void practice_6_3();
void practice_6_5();
void practice_6_6();
void practice_6_7();
void practice_6_10();
void practice_6_11();
void practice_6_17();
void example_p195();
int max(int a,const int *b);
void practice_6_21();
void swap_p(int *&r1,int *&r2);
void practice_6_22();
void print(const int *beg,const int *end);
void practice_6_23();
void sum(initializer_list<int> li);
void practice_6_27();